MSU (2-3, 1-1 Big Ten) held Michigan to just 28 yards rushing and Carlos Brown to just 15 yards.
"I think that was critical in this game. We knew we needed to stop the run and I think we were able to do that early on in the game," said MSU head coach Mark Dantonio.
"We couldn't run the ball, lamented UM coach Rich Rodriguez. "Some of it was that we couldn't get into a rhythm. We didn't have the ball and when we did they kept us to three and outs. I'll have to watch the film and see where our blocking was."
The result was that MSU turned Michigan into a one-dimensional team, but freshman quarterback Tate Forcier was sensational in bring UM back for the tie.
MSU led the contest 20-6 with less than five minutes remaining before Forcier hit Darryl Stonum on a 60-yard pass play to cut MSU's lead to 20-13.
The Spartans got ultra conservative, and with only :02 remaining, Forcier connected with Roy Roundtree to tie the score.
It was the MSU defense coming up big when Chris L. Rucker picked off Forcier on UM first possession of the overtime. Then it was Larry Caper running over several UM defenders en route to a 23 yard game winning touchdown.
"Larry Caper's run at the end of the game was huge," said Dantonio. "I'm extremely happy for our football team and I'm very proud of our team and how we represented and how we continued to play."
MSU next travels to Champagne to take on the Fighting Illini (1-3,0-2 Big Ten)